To increase their popularity, many television science shows are now written like detective shows. A "scientific mystery" is presented, evidence is collected and analyzed, scientists discuss theories that support the evidence, and a scientific consensus is stated. This detective-themed presentation captures viewer interest, which is also enhanced by scientific visualizations. These visualizations are a startling advance from the science films of my elementary school days, as parodied in many episodes of The Simpsons.[1-2]

Theia was just one of many protoplanets in the early Solar System whose fate was to either coalesce into a larger planet, or blasted apart into asteroids. Some of these protoplanets would have been as large as Mercury, and they may have existed for a considerable period, replicating many geological processes that exist on Earth. One such geological process would have been the formation of diamond under the high pressures existing at the protoplanetary cores.

It's conjectured that tens of such protoplanets between the size of the Moon and Mars formed the terrestrial planets of today's Solar System by crashing into each other and coalescing into our present planets.[4,8] This process would have happened in the first ten million years of the existence of the Solar System.[8] A 2015 examination of the diamonds found in the fragments of the 2008 Sudan meteor indicated that they were too large to have been created by impact forces between asteroids, so they might have been created in the core of one of these lost protoplanets.[10] The present study adds credence to this conjecture.

The Almahata Sitta meteorite is a rare type known as an ureilite, a class of carbon-rich stony meteorites that often contain clusters of nanoscale diamonds and don't originate from the Moon or Mars.[5,8-9,10] The contained diamonds are up to 100 micrometers in size, which is at least 100 times larger than nanodiamonds that form by impact, thus the conjecture that they were produced in a protoplanetary core.[6]

While the nanoscale diamonds could have formed at the core of a protoplanet of the size of Mercury or larger, they might also have formed just outside the core of another of Mars-size protoplanet or larger.[6] There are 480 ureilite meteorites, so there's potential for other insights into the protoplanets and early evolution of the Solar System.[7,9]